Opto-Electronic Module and Method for Manufacturing The Same

ABSTRACT

A method for manufacturing a device that includes an opto-electronic module includes creating a wafer stack including multiple active optical components mounted on a substrate wafer, and an optics wafer including multiple passive optical components. The optics wafer can include a blocking portion, which is substantially non-transparent for at least a specific wavelength range, and a transparent portion, which is substantially non-transparent for the specific wavelength range. Each opto-electronic module includes a substrate member, an optics member, an active optical component mounted on the substrate member, and a passive optical component. The optics member is directly or indirectly fixed to the substrate member. The opto-electronic modules can have excellent manufacturability, small dimensions and high alignment accuracy.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority from U.S. Provisional PatentApplication No. 61/521,818, filed on Aug. 10, 2011, the contents ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The disclosure relates to the field of opto-electronics and morespecifically to the packaging and manufacturing of opto-electroniccomponents. More particularly, it relates to opto-electronic modules andto methods of manufacturing the same and to appliances and to electronicdevices comprising such modules, in particular wherein the modulescomprise a light emitter. The invention relates to methods andapparatuses according to the opening clauses of the claims.

DEFINITION OF TERMS

“Active optical component”: A light sensing or a light emittingcomponent. E.g., a photodiode, an image sensor, an LED, an OLED, a laserchip.

“Passive optical component”: An optical component redirecting light byrefraction and/or diffraction and/or reflection such as a lens, a prism,a mirror, or an optical system, wherein an optical system is acollection of such optical components possibly also comprisingmechanical elements such as aperture stops, image screens, holders.

“Opto-electronic module”: A component in which at least one active andat least one passive optical component is comprised.

“Replication”: A technique by means of which a given structure or anegative thereof is reproduced. E.g., etching, embossing, imprinting,casting, molding.

“Wafer”: A substantially disk- or plate-like shaped item, its extensionin one direction (z-direction or vertical direction) is small withrespect to its extension in the other two directions (x- andy-directions or lateral directions). Usually, on a (non-blank) wafer, aplurality of like structures or items are arranged or provided therein,typically on a rectangular grid. A wafer may have opening or holes, anda wafer may even be free of material in a predominant portion of itslateral area. Although in many contexts, a wafer is understood to beprevailingly made of a semiconductor material, in the present patentapplication, this is explicitly not a limitation. Accordingly, a wafermay prevailingly be made of, e.g., a semiconductor material, a polymermaterial, a composite material comprising metals and polymers orpolymers and glass materials. In particular, hardenable materials suchas thermally or UV-curable polymers are interesting wafer materials inconjunction with the presented invention.

“Lateral”: cf. “Wafer”

“Vertical”: cf. “Wafer”

“Light”: Most generally electromagnetic radiation; more particularlyelectromagnetic radiation of the infrared, visible or ultravioletportion of the electromagnetic spectrum.

BACKGROUND

According to a known way of manufacturing an opto-electronic module, asingle packaged active optical component is arranged and aligned withrespect to a single passive active optical component, and the componentsare fixed with respect to each other.

U.S. Pat. No. 5,912,872 discloses an integrated optical apparatusincluding an optically transparent substrate with a light source and adetector mounted adjacent thereto. The substrate includes an opticalelement in a transmit path from the light source to a remote target. Theoptical element splits the light into more than one beam. The detectorreceives beams reflected by the target. All optical elements needed tocreate the more than one beam, direct the more than one beam onto thetarget and direct the more than one beam from the target to the detectorare on the substrate and/or any structure bonded to the substrate. Waysof manufacturing intregrated optical apparatuses on wafer level aredisclosed.

SUMMARY

It is one object of the invention to create an alternative way ofmanufacturing opto-electronic modules. More particularly, a particularlyfast way of manufacturing opto-electronic modules and/or a particularlysimple way of manufacturing opto-electronic modules shall be provided.In addition, the respective opto-electronic module, an electronic devicecomprising such an opto-electronic module and an appliance comprising amultitude of such opto-electronic modules shall be provided.

Another object of the invention is to provide opto-electronic moduleshaving a particularly good manufacturability and a correspondingmanufacturing method.

Another object of the invention is to provide opto-electronic modulesbeing manufacturable in a particularly low number of manufacturing stepsand a corresponding manufacturing method.

Another object of the invention is to provide a way of manufacturingopto-electronic modules which is a particularly stable manufacturingprocess.

Another object of the invention is to provide a method for manufacturingopto-electronic modules which is a particularly well suitable for massproduction.

Another object of the invention is to provide a method for manufacturingopto-electronic modules involving an improved handling, in particular asimplified handling.

Another object of the invention is to provide opto-electronic moduleshaving a particularly accurate alignment and a correspondingmanufacturing method.

Another object of the invention is to provide opto-electronic modules ofparticularly small dimensions.

Another object of the invention is to provide opto-electronic moduleswhich are well protected against undesired emission of light out of themodule and/or against undesired entry of light into the module.

Another object of the invention is to provide particularly smallelectronic devices comprising at least one opto-electronic module.

Further objects emerge from the description and embodiments below.

At least one of these objects is at least partially achieved byapparatuses and methods according to the patent claims.

GENERAL ASPECT(S) OF THE INVENTION

In a general aspect of the invention, the method is a method formanufacturing a device, the device comprising at least oneopto-electronic module, said method comprising the step of

-   c) creating a wafer stack comprising a first wafer, referred to as    substrate wafer, and a second wafer, referred to as optics wafer;    wherein a multitude of active optical components is mounted on said    substrate wafer, and said optics wafer comprises a multitude of    passive optical components, and wherein each of said opto-electronic    modules comprises at least one of said active optical components and    at least one of said passive optical components.

Such a wafer-level manufacturing requires a very small number ofmanufacturing steps only. And in addition, the achievable alignmentaccuracy (in particular for the lateral alignment) is very high. Also,the achievable process stability is high. Such a method is very wellsuited for mass production.

Furthermore, it is possible to provide packaged opto-electronic moduleswhich do not require further packaging before being used in an assembly.Already on wafer level, all necessary housing portions can be present,and the packaged opto-electronic packages including all their housingportions can be readily obtained carrying out a separating step (cf.step d) below).

The device can be, e.g., said opto-electronic module, but the device canalso be said wafer stack. And, the device can be an apparatus comprisingsaid opto-electronic module, e.g., an electronic device comprising saidopto-electronic module, such as a smart phone, or a photographic device,e.g., a photo camera or a video camera.

At least if the device is said opto-electronic module or comprises oneor two of said opto-electronic modules, the method typically comprisesthe step of

-   d) separating said wafer stack into a multitude of said    opto-electronic modules.

The separating (or dicing) can be accomplished by, e.g., by means of amechanical tool such as a saw (dicing saw or wafer saw) or a punchcutter, or by means of a laser.

Usually, already on wafer level and also in each opto-electronic module,each of said active optical components is allocated with at least one ofsaid passive optical components.

The active optical components can be packaged components, but it is alsopossible to provide that the active optical components are used in formof bare dies, i.e. in unpackaged form. The latter will usually allow tomanufacture smaller opto-electronic modules.

In the manufacture of the optics wafer and/or in the manufacture of thesubstrate wafer, replication can be used. This can contribute to anefficient manufacture of opto-electronic modules.

In one embodiment of the general aspect of the invention, the methodcomprises the step of

-   a) providing said substrate wafer;    and/or the step of-   b) providing said optics wafer.

In one embodiment of the general aspect of the invention, which may becombined with one or more of the before-addressed embodiments of thegeneral aspect, the method comprises the step of

-   e) placing said active optical components on said first wafer by    means of pick-and-place.

This can be accomplished, e.g., using a pick-and-place machine.Pick-and-place is a fast process which can be carried out well on waferlevel, providing a high placing accuracy.

In the general aspect of the invention, the opto-electronic modulecomprises

-   -   a substrate member;    -   an optics member;    -   at least one active optical component mounted on said substrate        member;    -   at least one passive optical component comprised in said optics        member;        wherein the optics member is directly or indirectly fixed to        said substrate member.

In a particular embodiment, outer bounds of a vertical silhouette of theopto-electronic module (i.e. the outer boarders of a shape described bythe opto-electronic module in a projection into a lateral plane)describe substantially a rectangular shape. This can effect an enhancedmanufacturability (cf. also the separating step d) mentioned above).

The invention comprises opto-electronic modules with features ofcorresponding methods according to the invention, and, vice versa, alsomethods with features of corresponding opto-electronic modules accordingto the invention.

The advantages of the opto-electronic modules basically correspond tothe advantages of corresponding methods, and, vice versa, the advantagesof the methods basically correspond to the advantages of correspondingopto-electronic modules.

In the general aspect of the invention, the appliance comprises amultitude of opto-electronic modules according to the invention, whereinthe appliance comprises a first wafer referred to as substrate wafer anda second wafer referred to as optics wafer, wherein the multitude ofsubstrate members is comprised in said substrate wafer, and themultitude of optics members is comprised in said optics wafer.

In the general aspect of the invention, the electronic device comprisesa printed circuit board (PCB) and an opto-electronic module according tothe invention mounted on said printed circuit board. Such an electronicdevice can be, e.g., a hand-held communication device such as a smartphone. The device could also be a photographic device, such as a photocamera.

The general aspect of the invention can be combined with several morespecific aspects of the invention which are discussed below.

First Aspect of the Invention

In a first aspect of the invention, said active optical components arelight emitting components. More particularly, said electro-opticalcomponents are light emitting members, such as light emitting diodes(LEDs), lasers, organic LEDs (OLEDs), e.g., for emitting, at leastprevailingly, visible light and/or infrared light. In particular, eachof said opto-electronic modules comprises exactly one light emittingmember.

In this first aspect of the invention, said first wafer will usually beprovided with no other types of active optical components but with lightemitting members, and accordingly, there will usually be no other typeof active optical components comprised in said opto-electronic modulesbut light emitting members.

For example, the opto-electronic modules are flash modules, i.e.components for emitting light flashes such as used in photography, e.g.,in compact photo cameras or in hand-held communication devices such assmart phones or hand-held communication devices. The manufactured devicecan, accordingly, also be an electronic device such as those namedbefore. In case that the opto-electronic modules are flash modules, saidlight emitting members are usually high-intensity short-pulse lightemitters such as LEDs used in today's photo cameras or smart phones. Inparticular, LEDs referred to as “high-brightness LEDs” can be used.

In this first aspect of the invention, the passive optical elementscomprise or are usually lens members. And in many applications, exactlyone lens member is provided in each of the opto-electronic modules.E.g., one lens, be it a diffractive or a refractive or a diffractive andrefractive lens, will be comprised in each opto-electronic module,usually allocated with one light emitting member such as ahigh-intensity short-pulse light emitter. A lens member comprises atleast one lens element, wherein it is possible that a lens member iscomprised of two or more transparent parts.

Second Aspect of the Invention

In a second aspect of the invention, said optics wafer and said opticsmember, respectively, comprise at least one portion, referred to asnon-transparent portion or blocking portion, which is at leastsubstantially non-transparent for at least a specific wavelength range,and at least one other portion, referred to as transparent portion,which is at least substantially transparent for at least said specificwavelength range. Note that the term wavelength range does not implythat it is contiguous. Usually, said specific wavelength range ischaracteristic for at least a portion of said multitude of activeoptical components, in particular for all of said multitude of activeoptical components. E.g., in case of a detector as an active opticalcomponent, said specific wavelength range is the wavelength range oflight detectable by the detector or a portion thereof, and in case of alight emitting component as an active optical component, said specificwavelength range is the wavelength range of light emittable by the lightemitting component or a portion thereof. When referring to “transparent”or “non-transparent” in the present patent application, it is referredto such a wavelength range.

A blocking portion can hold (fix) one or more transparent portions and,at the same time, inhibit unwanted propation of light, e.g., byfunctioning as an aperture and/or by avoiding that light exits or entersthe opto-electronic module along an undesired path; the latter inparticular when the blocking portion forms a portion of a housing of theopto-electronic module.

It can well be sufficient to provide that an optics member comprises oreven consists of one blocking portion and one transparent portion. Anoptics wafer, however, will usually comprise a multitude of transparentportions, typically one transparent portion per associated passiveoptical component, while it is possible to provide that one blockingportion is sufficient. It can be provided that an optics wafer comprisesor even consists of one blocking portion and a multitude of transparentportions.

It can be provided that the addressed transparency and non-transparency,respectively, is due to the material of which said transparent portionand said blocking portion, respectively, are made.

In particular, said blocking portion can be made substantially of onematerial, e.g., a polymer material such as a cured curable epoxy resin.Particularly suitable materials for manufacturing said blocking portionare hardenable materials, like curable materials, wherein curing can beaccomplished by heating or by irraditation with light, e.g., ultravioletlight, wherein heating will in many cases be more suitable thanirradiation because of the non-transparent properties of the blockingportion.

The blocking portion can be manufactured, e.g., by means of replication,more particularly using embossing. This can be very efficient in termsof providing a stable manufacturing process suitable for massproduction. In an exemplary replication process using embossing, astructured surface is embossed into a liquid, viscous or plasticallydeformable material (replication material), then the material ishardened, e.g., by curing using ultraviolet radiation or heating, andthen the structured surface is removed. Thus, a replica (which in thiscase is an negative replica) of the structured surface is obtained.Suitable materials for replication are, e.g., hardenable (moreparticularly curable) polymer materials, e.g., epoxy resins, or otherreplication materials, i.e. materials which are transformable in ahardening step (more particularly in a curing step) from a liquid,viscous or plastically deformable state into a solid state. Replicationis a known technique, cf., e.g., WO 2005/083789 A2 for more detailsabout this.

It is possible to provide that said blocking portion (of said opticswafer and of said optics member) is embodied as a unitary part, inparticular if formed by replication. This can be very efficient in termsof simplifying the manufacturing process.

The optics wafer and also the opto-electronic module can be designedsuch that each transparent portion is laterally enclosed by the (or a)blocking portion.

Each of the transparent portions of the optics wafer and of the opticsmembers usually comprises one or several of the passive opticalcomponents, usually rather one.

Also in the manufacture of transparent portions, a replication step maybe comprised, in particular in the manufacture of the passive opticalcomponents. Correspondingly, the transparent parts may, at least inpart, be made of a hardened hardenable material, in particular of acured curable material, e.g., a polymer material such as an epoxy resin.

The manufacture of the device, in particular of the wafer stack or ofthe opto-electronic module, may comprise the step of

-   d) manufacturing said optics wafer;    wherein step d) comprises the steps of    -   d1) providing a precursor wafer substantially made of        non-transparent material having openings in places where said        transparent portions are supposed to be located;    -   d5) producing in each of said openings at least one of said        passive optical components, usually exactly one.

As mentioned before, the terms transparent and non-transparent refer tothe above-mentioned specific wavelength range.

Steps d1) and d5) can contribute to a particularly efficient way ofmanufacturing said optics wafer.

The precursor wafer can comprise said at least one blocking portion.There are different ways of manufacturing a precursor wafer. One way ofmanufacturing the precursor wafer makes use of replication, e.g., asdescribed above. This can be very efficient. When a hardening step iscarried out during said replication, e.g., a curing step, this willrather be done by heating, because a non-transparency of thenon-transparent material of the blocking portion may in many cases beaccompanied by a non-transparency for radiation that would be used foraccomplishing radiation hardening.

An alternative to replication is creating said openings by means ofdrilling or etching. If molding is used for manufacturing the precursorwafer, using molding, duroplastic injection molding can be aparticularly suitable method for various applications.

There are at least two ways of producing the transparent portions andmore particularly the passive optical components, i.e. to carry out stepd5):

One can manufacture the transparent portions or at least the passiveoptical components as unitary parts, e.g., by replication, such that thepassive optical components, e.g., lenses, are located in the openings ofthe precursor wafer. Ways of producing lenses in openings in a wafer byreplication are disclosed, e.g., in US 2011/043923 A1.

Or, one can manufacture the transparent portions or at least the passiveoptical components as a part composed of at least two parts.Particularly interesting is to firstly manufacture a semi-finished partcomprising transparent elements, one in each of the openings of theprecursor wafer, wherein each of the transparent elements has twoopposing at least approximately flat surfaces substantiallyperpendicular to the vertical direction.

Accordingly, step d) in that case comprises the step of

-   -   d2) at least partially filling said openings with transparent        material.

Typically, during step d2), said transparent material is in a liquid orviscous state, and subsequent to step d2), the step of

-   -   d3) hardening said transparent material;        is carried out. In particular, wherein said hardening comprises        curing.

Step d2) can be carried out using a dispenser. Therein, one or severalof said openings can be filled at a time. An alternative to using adispenser is using a squeegee process, e.g., like used in ascreen-printing process.

A so-obtained semi-finished part typically is a wafer having no holespenetrating the wafer (or at least no holes penetrating the wafer in theregions where the transparent portions are). Depending on the shape ofthe precursor wafer, more particularly of corrugations or protrusions invertical directions it has (as visible in a vertical cross-section), itis possible and may be useful to apply a polishing step to theso-obtained wafer before proceeding forming the passive opticalcomponents.

If steps d2) and d3) are carried out, step d5) may comprise the step of

-   -   d55) producing said multitude of passive optical components by        producing on each of said multitude of transparent elements at        least one optical structure.

Usually, said at least one optical structure is provided forinfluencing, in particular for guiding light, more particularly forredirecting light. E.g., said optical structures may be or comprise lenselements, but prisms, mirrors and optical structures making use of totalinternal reflection (TIR) may be provided, too.

Step d55) can be carried out, e.g., using replication, e.g., usingembossing, e.g., in a way as described in more detail above for blockingportions.

As will be appreciated, the second aspect of the invention can also becombined with the first aspect of the invention. This can, e.g., help toensure that emitted light leaves an opto-electronic module only alongdesired paths.

Third Aspect of the Invention

The substrate wafer can be—at least in the region where said activeoptical components are mounted—non-transparent. But in a third aspect ofthe invention, said active optical components each have an opticallyactive surface, and the substrate wafer is, at least in part,transparent, and the active optical components are mounted on thesubstrate wafer in such a way that their respective optically activesurface faces said substrate wafer in a location where the substratewafer is transparent. The term “transparent in part” refers again to thebefore-mentioned specific wavelength range. The optically active surfaceis a portion of the surface of an active optical component where lightcan enter the active optical component to be detected by the activeoptical component or from which light is emittable by the active opticalcomponent. The latter is usually the case when the opto-electronicmodule is a light emitter such as an LED, the former when theopto-electronic module is a detector such as a photo diode.

Such a wafer may be, e.g., a transparent plate such as a glass plate ora plate of transparent polymer material. For some applications, it canbe useful if not the whole substrate is transparent, but only portionsthereof. This can be useful for guiding light more precisely and forinhibiting undesired light propagation, e.g., for producing abetter-defined light cone, or for detecting light from pre-defineddirections of incidence only. E.g., the substrate wafer can be realizedsimilarly to what has been described above in the second aspect of theinvention for the optics wafer. All what has been described thereconcerning the optics wafer or its manufacture may apply to thesubstrate wafer of the third aspect. Therein, it is optional (and notrequired) that the substrate wafer comprises passive optical components.The substrate wafer can, e.g., be what has been described above as aprecursor wafer, holes or openings in the substrate wafer allocated withoptically active surfaces of the active optical components serving astransparent portions, non-transparent portions surrounding the holes oropenings blocking light emitted by or detectable by the active opticalcomponents. Or, the substrate can, e.g., be what has been describedabove as semi-finished part, the transparent elements in the substratewafer allocated with optically active surfaces of the active opticalcomponents serving as transparent portions, non-transparent portionssurrounding the holes or openings blocking light emitted by ordetectable by the active optical components.

It is possible that the substrate wafer is embodied as a printed circuitboard (PCB) or as a printed circuit board assembly (PCBA). This would bea combination of the third with the fourth aspect of the invention (seebelow). The PCB or PCBA could, e.g., have holes, e.g., manufactured bydrilling, which serve as transparent portions allocated with theoptically active surface of the active optical components, andelectrical connections could be provided between electrical contacts ofthe active optical components and electrical contacts of the PCB. Suchan electrical connection may at the same time serve as a mechanicalconnection fixing the active optical components to the PCB, whereinpossibly, further provisions may be present contributing to a fixture ofthe active optical components to the substrate wafer. The printedcircuit board (PCB) material of which the PCB is substantially made(disregarding the metals) may, e.g., be a rigid or a flexible PCBmaterial, a fiber-reinforced or not fiber-reinforced material, it may beepoxy-based such as FR4 or polyimide.

The active optical elements can be placed on the substrate wafer bymeans of pick-and-place, e.g., using a pick-and-place machine known inelectronics industry.

It is possible to fix the active optical components to the substratewafer, e.g., by bonding them thereto, e.g., by gluing, in particularusing thermosetting and/or UV-curing glue. An electrical connection ofthe active optical components to the substrate wafer is no necessity,but an option. If, e.g., the active optical components are notelectrically connected to the substrate wafer, it is possible to providethat electrical contacts of the active optical components are used aselectrical contacts of the manufactured opto-electronic modules, or,e.g., another (additional, second) substrate wafer can be provided forelectrically contacting the active optical components.

In the latter case, that additional (second) substrate wafer can providefor the electrical contacts of the opto-electronic module to bemanufactured. It is to be noted that in some cases, e.g., when theelectrical connection to the additional (second) substrate wafer isaccomplished by soldering, the (lateral) positioning accuracy of theactive optical components achievable by a suitable fixing to the firstsubstrate wafer can readily be by far superior to the accuracyachievable by a fixing to the second substrate wafer. In such a case,the electrical connections to the second substrate wafer will usually becreated after (or at least not before) creating the fixing to the firstsubstrate wafer.

The additional (second) substrate wafer can, e.g., be a PCB or a PCBA.If, e.g., the footprint of the passive optical components is smallerthan desired for the opto-electronic modules to be manufactured, theadditional substrate wafer can thus be used for widening the footprintand provide a footprint desired for the opto-electronic module.

Details concerning electrical contacts of the opto-electronic modulesand of possibilities to electrically contact the active opticalcomponents which may find application within the third aspect of theinvention are given below in conjunction with the fourth aspect of theinvention.

As will be appreciated, the third aspect of the invention can becombined with the first and/or with the second aspect of the invention.

It is readily understood that, although prevailingly, the wafers havebeen mentioned above, the same or similar considerations apply to thecorresponding members of the opto-electronic modules and to theopto-electronic modules manufactured using the described wafers. Thisalso applies to the text further below.

Fourth Aspect of the Invention

In a fourth aspect of the invention, an electrical connection is presentbetween the active optical components and the substrate wafer. Thisallows to rewire the electrical connections of the active opticalcomponents using the substrate wafer. The substrate wafer can be, e.g.,a PCB or PCBA. Usually, the substrate wafer will predominantly be madeof non-transparent material; in conjunction with the third aspect of theinvention, it is possible to provide transparent portions in thesubstrate wafer, e.g., in form of holes or openings in the substratewafer.

The electrical connections between the active optical components and thesubstrate wafer can be accomplished by means of, e.g., through-holetechnology or surface mount technology (SMT), in particular if theactive optical components are provided as packaged components. But inparticular if the active optical components are provided as bare dies,the electrical connections between the active optical components and thesubstrate wafer can be accomplished by means of, e.g., wire bonding orflip chip technology or using conductive glue or by means of acombination of at least two of these; e.g., electrically andmechanically connecting the bare die with its non-light-emitting side tothe substrate wafer by means of conductive glue and creating anelectrical connection between the opposite (light-emitting) side of thebare die to the substrate wafer by means of wire bonding.

The electrical contacts of the opto-electronic modules can, also in theother aspects of the invention, be provided, e.g., by contact pads withor without attached solder balls or by lead frame contacts. Theelectrical contacts of the substrate wafer can, also in the otheraspects of the invention where they are present, be provided by, e.g.,contact pads or through-holes.

Generally, the fourth aspect of the invention can be combined with thefirst and/or the second and/or the third aspect of the inventiondescribed above. With respect to the combination of a fully transparentsubstrate wafer (which is a possible embodiment of the third aspect)with the fourth aspect, it is to be noted that it is possible to providetransparent materials for accomplishing electrical contacts, e.g.,transparent conductive oxides such as ITO (indium tin oxide), ZnO (zincoxide) or SnO₂ (tin oxide).

In a combination of the fourth and the third aspect of the invention, itis possible to provide that there are two substrate wafers provided, ashas already been mentioned above in conjunction with the third aspect ofthe invention. Therein, it is possible to provide that the activeoptical components are firstly placed on and (mechanically) fixed to asubstrate according to the third aspect (being transparent or havingtransparent portions), and then the electric connection to a substrateaccording to the fourth aspect is accomplished. But it is also possibleto reverse this order, i.e. to firstly place the active opticalcomponents on a substrate according to the fourth aspect and establishthe electrical connections between the active optical components andthat substrate, and then to (mechanically) fix the active opticalcomponents to the second (at least partially transparent) substrate. Andit is even possible to place the active optical components on one ofthese substrates and then to establish both connections (the electricalto the one and the mechanical to the other substrate wafer) atsubstantially the same time, e.g., by heating, e.g., the heating curinga bonding material (for the—mechanical—connection to the substrateaccording to the third aspect) and also melting a solder paste or curingan electrically conductive glue (for the electrical connection to thesubstrate according to the fourth aspect).

In an embodiment in which the active optical components are connected totwo substrate wafers, e.g., like described before, the active opticalcomponents will usually be arranged between these two wafers, i.e. thatone substrate wafer to which the active optical components are merelymechanically fixed will be arranged on one side of the active opticalcomponents, usually on that side, towards which said optically activesurfaces of the active optical components face, and the other substratewafer (to which the active optical components are electricallyconnected) will be arranged on another side of the active opticalcomponents (usually on the side which is opposite to that side, to whichsaid optically active surfaces of the active optical components face).

More generally, one can also provide that the (mechanical) fixture tothe one substrate wafer (according to the third aspect of the invention)can be dispensed with, such that in a corresponding wafer stack, theactive optical components are arranged between that substrate wafer anda substrate wafer according to the fourth aspect, being electricallyconnected to the latter. The electrical connection will usually alsoprovide a mechanical connection to the respective substrate wafer, andit is also possible to provide that the electrical connection can becomplemented by an additional mechanical fixing, e.g., by bonding of theactive optical component to the substrate according to the fourth aspectof the invention.

Fifth Aspect of the Invention

In a fifth aspect of the invention, means are provided which ensure awell-defined (and usually also pre-defined) distance between saidsubstrate wafer and said optics wafer. A precise vertical arrangement ofactive and passive optical components is generally of importance formanufacturing quality opto-electronic modules. (Note that the lateralalignment is also important; but this can usually be well accomplishedmanufacturing on wafer-scale as is generally proposed in the presentpatent application.) More specifically, these means can be, at least inpart, non-transparent, e.g., by being made substantially of anon-transparent material, wherein such a material can in particularly bea polymer material and/or a hardened hardenable material, such as acurable material, e.g., a curable expoxy resin. This can help to inhibitlight propagation in undesired directions, similar as has been explainedfor the optics wafer with at least one blocking portion in conjunctionwith the second aspect of the invention.

Furthermore, the before-addressed means may form a part of a housing ofthe opto-electronic modules to be manufactured. This can greatly enhanceand/or simply the manufacture of the opto-electronic modules, and it canin that case be particularly useful to provide the before-addressed (atleast partial) non-transparency of the means.

There are at least three ways of providing such means. One is to providethat these means are provided in form of a wafer, referred to as spacerwafer, the spacer wafer being not identical with said substrate wafer orsaid optics wafer. Such a spacer wafer can substantially be made of ahardened hardenable material such as cured curable material, e.g., anepoxy resin. And such a spacer wafer may be manufactured usingreplication. Another way is to provide that these means constitute aportion of the optics wafer. This can help to minimize the number ofmanufacturing steps. This is as if optics wafer and spacer wafer werethe same part, and/or, e.g., at least a portion of the spacer wafer(usually the complete spacer wafer) and at least a portion of the opticswafer form a unitary part. The third way is to provide that these meansconstitute a portion of the substrate wafer. Also this can help tominimize the number of manufacturing steps. This is as if substratewafer and spacer wafer were the same part, and/or, e.g., at least aportion of the spacer wafer (usually the complete spacer wafer) and atleast a portion of the substrate wafer form a unitary part. In case aspacer wafer is provided which is not identical with the optics wafer orwith the substrate wafer, that spacer wafer can, of course, fulfill, inaddition, further functions, such as the before-mentioned possibility tocontribute to the (outer) housing of manufactured opto-electronicmodules and to block undesired light propagation.

When during the manufacture of the optics wafer or of the substratewafer, replication is used, this possibly can be useful and savemanufacturing steps. E.g., a unitary part can be manufactured by meansof replication which is made of, e.g., cured, non-transparentreplication material and which forms at least one blocking portion(non-transparent portion) of the optics wafer or of the substrate waferand also forms means for defining a distance (usually a verticaldistance) between active optical components and passive opticalcomponents.

Sixth Aspect of the Invention

A sixth aspect of the invention refers to the order of manufacturingsteps during manufacturing a device comprising at least oneopto-electronic module, more particularly during manufacturing anopto-electronic module. it is suggested to firstly provide an opticswafer and means for ensuring a well-defined vertical distance betweenpassive and active optical components, wherein these means or at least aportion thereof may be comprised in the optics wafer or may be adistinct part and in particular a unitary part, and/or wherein thesemeans are a composed of two or more parts. Only when this wafer isprovided or, if the optics wafer and said means comprise at least twoseparate parts, when the corresponding two or more wafers are providedand fixed with respect to each other, the active optical components areattached to or mounted on said means, usually individually, e.g., usinga pick-and-place process, or wafer-wise, i.e. by attaching a wafer onwhich a multitude of active optical components are mounted.

This can make it possible to achieve a particularly high alignmentprecision of the active optical components with respect to the passiveoptical components.

This sixth aspect can be combined with one or more of the first to fifthaspect of the invention.

For example, a light-emitting opto-electronic module such as a flashmodule (cf. first aspect of the invention) is manufactured including themanufacture of an optics wafer which may be partially non-transparent(cf. second aspect of the invention), wherein a spacer wafer which maybe substantially non-transparent (cf. fifth aspect of the invention) isprovided and attached to the optics wafer, or the optics wafer comprisesprotrusions functioning like a spacer wafer.

Then, the active optical components are attached (usually mechanicallyand usually not electrically). This may be accomplished bypick-and-place of the active optical components onto the optics waferor, if present, onto the spacer wafer. Or, the active optical componentsare attached by attaching to the optics wafer or to the spacer waferanother wafer, namely the substrate wafer, on which the active opticalcomponents are arranged, in which case the active optical componentshave previously been mounted on or attached to that additional wafer(substrate wafer).

Yet another possibilty to attach the active optical components is toattach to the optics wafer or, if present, to the spacer wafer, anotherwafer, namely the substrate wafer, and then, the active opticalcomponents are mounted on the substrate wafer, wherein it is alsopossible to carry out the steps of attaching the substrate wafer to theother wafer and of attaching the active optical components to thesubstrate wafer in one process step and therefore substantiallysimultaneously, e.g., by heating (such as in a reflow oven), the heatingaccomplishing a hardening or curing of bonding material such as glueand/or solder.

However the time sequence of attaching the substrate wafer and attachingthe active optical components to the substrate wafer, the substratewafer can be fully or partially transparent (cf. third aspect of theinvention), and the active optical components can have an electricalconnection to the substrate (cf. fourth aspect of the invention), e.g.,the substrate being a PCB or PCBA, or no electrical connection betweenthe active optical components and the substrate wafer is provided. Inparticular in the latter case, electrical contacts of the active opticalcomponents may also serve as electrical contacts of the opto-electronicmodule.

Thus, in the sixth aspect of the invention, the following method may beprovided:

A method according to the general aspect of the invention, wherein thewafer stack comprises means for ensuring a well-defined distance betweensaid active optical components and said passive optical components, themethod comprising,

-   -   in case said means are comprised in said optics wafer, the steps        of        -   f) providing said optics wafer, said optics wafer            comprising, as said means, vertical protrusions for ensuring            said well-defined distance between said active optical            components and said passive optical components; and        -   h) attaching said active optical components to said wafer            stack;    -   wherein step h) is not carried out before step f) is carried        out;    -   in case said means are not comprised in said optics wafer, the        steps of        -   g1) providing said optics wafer; and        -   g2) providing, as said means, at least one spacer wafer for            ensuring a well-defined distance between said active optical            components and said passive optical components;        -   h′) attaching said active optical components to said wafer            stack;    -   wherein step h) is not carried out before steps g1) and g2) are        carried out.

Further embodiments and advantages emerge from the dependent claims andthe figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, the invention is described in more detail by means of examplesand the included drawings. The figures show schematically:

FIG. 1 a cross-sectional view of an opto-electronic module;

FIG. 2 various cross-sectional views of constituents of the module ofFIG. 1;

FIG. 3 a cross-sectional view of wafers for forming a wafer stack formanufacturing a multitude of modules of FIG. 1;

FIG. 4 a cross-sectional view of a wafer stack for manufacturing amultitude of modules of FIG. 1;

FIG. 5 a diagrammatical illustration of a manufacturing step in across-sectional view;

FIG. 6 a diagrammatical illustration of a manufacturing step in across-sectional view;

FIG. 7 a diagrammatical illustration of a manufacturing step in across-sectional view, a semi-finished part is shown;

FIG. 8 a diagrammatical illustration of a manufacturing step in across-sectional view;

FIG. 9 a diagrammatical illustration of a cross-section through anoptics wafer;

FIG. 10 a cross-sectional view of a semi-finished part having astructured surface;

FIG. 11 a cross-sectional view of a wafer stack illustrating themanufacture of opto-electronic modules;

FIG. 12 an opto-electronic module in a cross-sectional view;

FIG. 13 an opto-electronic module in a cross-sectional view;

FIG. 14 an opto-electronic module in a cross-sectional view;

FIG. 15 an opto-electronic module in a cross-sectional view;

FIG. 16 an opto-electronic module in a cross-sectional view;

FIG. 17 an opto-electronic module in a cross-sectional view;

FIG. 18 an opto-electronic module in a cross-sectional view;

FIG. 19 an opto-electronic module in a cross-sectional view.

The reference symbols used in the figures and their meaning aresummarized in the list of reference symbols. The described embodimentsare meant as examples and shall not confine the invention.

DETAILED DESCRIPTION

FIG. 1 shows a schematic cross-sectional view of an opto-electronicmodule 1, e.g., a light-emitting module such as a flash light modulelike usuable in photographic cameras or in smart phones. The illustratedcross-section is a vertical cross-section. FIG. 2 shows variousschematic lateral cross-sectional views of constituents of the module ofFIG. 1, wherein the approximate positions of these lateralcross-sections are indicated in FIG. 1 by s1 to s5 and dashed lines. Fors4 and s5, the direction of view is indicated by arrows.

Module 1 comprises several constituents (P, S, O, B) stacked upon eachother in a direction through which the term “vertical” is defined; itcorresponds to the z direction (cf. FIG. 1). Directions in the x-y plane(cf. FIG. 2) perpendicular to the vertical (z) direction are referred toas “lateral”.

Module 1 comprises a substrate member P, a spacer member S, an opticsmember O and a baffle member B stacked upon each other. Substrate memberP is or comprises, e.g., a printed circuit board on which an activeoptical component E is mounted. The printed circuit board (PCB) can morespecifically also be referred to as an interposer. The active opticalcomponent E can in particular be an emission member E for emittinglight, in particular for emitting light flashes (high-intensity shortlight pulses), e.g., a light-emitting diode (LED). Electrical contactsof emission member E (not shown in FIG. 1) are electrically connected tothe outside of module 1, where solder balls 7 are attached. Instead ofproviding solder balls 7, it would also be possible to provide contactpads at substrate member P, which are not or which are at a later timeprovided with solder balls or conductive glue.

This way, module 1 can be mounted on a printed circuit board 9, e.g., insurface mount technology (SMT), next to other electronic components (notshown). Printed circuit board 9 may be a constituent of an electronicdevice 10 such as a hand-held communication device or a photo camera. Inparticular, device 10 can be a smart phone. Module 1 is particularlysuitable for such applications because it can be manufactured having aparticularly small size.

Spacer member S has an opening 4 in which emission member E is arranged.Emission member E is laterally encircled by spacer member S.

Spacer member S may fulfill several tasks. It can ensure a well-defineddistance between substrate member P and optics member O (through itsvertical extension) which helps to achieve well-defined light paths fromemitting member E through optics member O to the outside of module 1.Furthermore, spacer member S forms a portion of the outside walls ofmodule 1. In particular if spacer member S is at least substantiallynon-transparent for light of a specific wavelength range, moreparticularly for light of wavelengths emittable by emission member E, itcan help to inhibit an emission of light from portions of the module 1from which an emission of light is undesired.

Typically, separating member S is made of a polymer material, inparticular of a hardened hardenable or more specifically cured curablepolymer material, e.g., of an epoxy resin.

Optics member O comprises a blocking portion b and a transparent portiont, the latter for allowing light emitted by emission member E to leavemodule 1.

Blocking portion b is substantially non-transparent for light of aspecific wavelength range, in particular for light of thebefore-mentioned specific wavelength range, e.g., by being made of asuitable (polymer) material. Transparent portion t comprises a passiveoptical component L or, more particularly and as an example, a lensmember each, for light guidance, more particularly for guiding lightemitted by emission member E (in a desired way). Lens member L may,e.g., comprise, as shown in FIG. 1, two lens elements 5 in close contactto a transparent element 6. Transparent element 6 can have the samevertical dimension as optics member O where it forms blocking portion b,such that optics member O where it forms blocking portion b togetherwith transparent element 6 describes a (close-to-perfect) flat solidplate shape. Lens element 5 redirects light by refraction (cf. FIG. 1)and/or by diffraction. E.g., lens element may be of generally convexshape (as shown in FIG. 1), but may be differently shaped, e.g.,generally or partially concave.

Baffle member B, which is optional in opto-electronic module 1, allowsto confine a cone of light emitted by the opto-electronic module 1; itmay function as an aperture. But it may also serve to mechanicallyprotect passive optical component L. Usually, baffle member B will havea transparent region 3 which may be embodied as an opening or by meansof transparent material. Baffle member B can, outside transparent region3, be made of a material substantially attenuating or blocking lighthaving a wavelength in a specific or in one of the before-addressedwavelength range, or it could be provided with a coating having such aproperty, wherein the latter will usually be more complex tomanufacture. The shape of baffle member B or more precisely oftransparent region 3, can, of course, be different from what is shown inFIGS. 1 and 2, e.g., describe cone-like shapes or describe a truncatedpyramid.

The lateral shape not only of transparent region 3, but also oftransparent portion t and of opening 4 do not have to be circular, butmay have other appearances, e.g., polygonal or rectangular with roundedcorners.

Module 1 is an opto-electronic component, more precisely a packagedopto-electronic component. The vertical side walls of module 1 areformed by items P, S, O and B. A bottom wall is formed by substratemember P, and a top wall by baffle member B or by baffle member Btogether with optics member O.

As is well visible in FIG. 2, the four items P, S, O, B, which can forthe reasons above also be referred to as housing components, all havesubstantially the same lateral shape and lateral dimensions. This isrelated to a possible and very efficient way of manufacturing suchmodules 1 which is described in more detail below referring to FIGS. 3and 4. These housing components P, S, O, and B are all of generallyblock- or plate-like shape or more generally of generally rectangularparallelepiped shape, possibly having holes or openings (such as bafflemember B and spacer member S do) or projections (such as optics member Odoes).

It is possible to provide modules which are designed according to thesame principles as discussed above, but comprising, instead of or inaddition to emission member E, one or more electric or electroniccomponents, in particular active optical components, such as one or moreadditional light sources, or one or more integrated circuits, or a lightdetector.

The active optical components comprised in a module (such as emissionmember E in the example of FIG. 1) can be packaged or unpackagedelectronic components. For electrically contacting substrate member P,technologies such as wire-bonding or flip chip technology or contactingusing electrically conductive paste or glue, or also any other knownsurface mount technology may be used, or even conventional through-holetechnology. More details and examples will be given below, inconjunction with other figures.

The typically envisaged dimensions of opto-electronic modules 1described in the present patent application are laterally below 15 mm,more typically between 0.5 mm and 8 mm, more particularly between 1 mmand 5 mm, and vertically below 30 mm, more typically between 1 mm and 15mm, more particularly between 1.5 mm and 10 mm. But generally, alsoother dimensions may be applicable.

FIG. 3 shows a schematical cross-sectional view of wafers for forming awafer stack for manufacturing a multitude of modules as shown in FIG. 1.It is possible to manufacture such modules 1 (practically) completely onwafer-scale, of course with a subsequent separation step. Although FIGS.3 and 4 only show provisions for three modules 1, there will usually bein one wafer stack 2 provisions for at least 10, rather at least 30 oreven more than 50 modules in each lateral direction. Typical dimensionsof each of the wafers are: laterally at least 5 cm or 10 cm, and up to30 cm or 40 cm or even 50 cm; and vertically (measured with nocomponents arranged on substrate wafer PW) at least 0.2 mm or 0.4 mm oreven 1 mm, and up to 6 mm or 10 mm or even 20 mm. But generally, alsoother dimensions may be applicable.

Four wafers are sufficient for manufacturing a multitude of modules asshown in FIG. 1: A substrate wafer PW, a spacer wafer SW, an opticswafer OW and a baffle wafer BW. Each wafer comprises a multitude of thecorresponding members comprised in the corresponding module I (cf. FIGS.1 and 2), usually arranged on a rectangular lattice, typically with alittle distance from each other for a wafer separation step.

Substrate wafer PW can be embodied as a PCB of standard PCB materials,with a multitude of passive optical components E mounted thereon on oneside, and provided with solder balls 7 on the other one side. Theemission members E can be placed on substrate wafer PW by pick-and-placeusing standard pick-and-place machines well-known in electronicsindustry.

In order to provide maximum inhibition of light emission from undesiredparts of module 1, each of the wafers PW, SW, OW, BW can substantiallybe made of a material substantially non-transparent for light emitted byemission members E, of course except for transparent areas such astransparent portions t and transparent regions 3.

Wafers SW and BW and possibly also all or a portion of wafer OW can beproduced by replication. In an exemplary replication process, astructured surface is embossed into a liquid, viscous or plasticallydeformable material, then the material is hardened, e.g., by curingusing ultraviolet radiation or heating, and then the structured surfaceis removed. Thus, a replica (which in this case is an negative replica)of the structured surface is obtained. Suitable materials forreplication are, e.g., hardenable (more particularly curable) polymermaterials or other replication materials, i.e. materials which aretransformable in a hardening step (more particularly in a curing step)from a liquid, viscous or plastically deformable state into a solidstate. Replication is a known technique, cf., e.g., WO 2005/083789 A2for more details about this.

In case of optics wafer OW, replication using embossing or molding maybe used for obtaining the non-transparent portions (blocking portion b).It would also be possible to provide holes, where transparent portions tare supposed to be, by means of drilling or etching.

Subsequently, a so-obtained precursor wafer is provided with lensmembers L, so as to yield optics wafer OW. This may be accomplished bymeans of replication, e.g., forming lens members L as a unitary parts,e.g., as described in US 2011/0043923 A1. The lens members L can,however, also be manufactured in a different way which will be describedreferring to FIGS. 5 to 9. FIGS. 5 to 8 are schematized diagrammaticalillustrations of corresponding manufacturing steps, in a cross-sectionalview, wherein FIG. 7 illustrates a semi-finished part referenced ow.FIG. 9 is a schematized diagrammatical illustration of a cross-sectionthrough a so-obtained optics wafer OW.

This particular way of manufacturing is based on semi-finished part owshown in FIG. 7 being a wafer comprising transparent elements 6 withinholes by which transparent portions t are defined. This can beparticularly useful when lens members L each describe at least one apex,and those apices are located outside a vertical cross-section of theoptics wafer OW. Such a semi-finished part ow is (usually, and in theexemplary case illustrated in the FIGS. 1-9) a flat disk-like waferhaving no holes penetrating the wafer in the transparent portions t andhaving virtually no or only shallow surface corrugations, such surfacecorrugations usually being concave, i.e. not extending beyond the wafersurface as described by the blocking portions b.

A semi-finished part ow like that (cf. FIG. 7) can be obtained startingfrom a flat precursor wafer 8 (typically made of one material) havingholes or openings 11 where the transparent portions t are supposed to be(cf. FIG. 5) and then filling the holes 11 with transparent material T,e.g., using a dispensing process (cf. FIG. 6), either filling the holes11 in the precursor wafer 8 one-by-one, e.g., using a dispenser such asused for underfilling processes in flip-chip technology or the like, orby filling several holes 11 at once, e.g., using a squeegee process(e.g. as known from screen printing) or a dispenser with several hollowneedles outputting material T.

During the dispensing (cf. FIG. 6), the wafer can be placed on a flatsupport, e.g. on a support layer 12, e.g., made of a silicone, whichagain sits on a support substrate 13, e.g., a glass plate, for reasonsof stability. Care has to be taken order to prevent the formation of airbubbles or cavities in the dispensed material T, since this woulddegrade the optical properties of the lens members L to be produced.E.g., one can carry out the dispensing in such a way that wetting of thewafer material starts at an edge formed by the wafer and an underlyingsupport layer 12 (or in a place close to such an edge), e.g., bysuitably guiding a hollow needle outputting the material T close to suchan edge. Subsequently, the dispensed material is cured, e.g., by heat orUV radiation, so as to obtain hardened transparent material. This yieldsthe semi-finished part ow shown in FIG. 7.

Convex meniscuses possibly formed this way can be flattened bypolishing, so as to obtain a transparent element 6 having parallelsurfaces adjusted to the wafer thickness wherein it is possible to carryout the polishing in such a way that the wafer thickness is reduced to adesired value. Then, by means of replication, lens elements 5 areapplied to one or both sides (top and bottom side) of semi-finished partow. FIG. 8 illustrates the state after adding lens elements 5 on oneside only. In case of concave meniscuses of the transparent elements,the replication can take place on these, wherein the amount of appliedreplication material might have to be adjusted accordingly.Alternatively, polishing may be used, wherein during polishing, not onlysurfaces of transparent elements 6 are flattened, but also the blockingportion b.

FIG. 9 illustrates an optics wafer OW as obtained in thebefore-described way, with lens elements 5 added on both sides.

In many cases, it is possible to combine the functionality of two ormore wafers which would be adjacent in the wafer stack in one singlewafer (“combined wafer”). E.g., a suitably designed optics wafer canreplace the following wafers shown in FIGS. 3 and 4: wafers OW and SW;or wafers OW and BW; oder wafers BW, OW and SW.

Accordingly, it is possible to provide that said spacer wafer SW isobsolete in the sense that a particular kind of optics wafer is providedwhich functionally replaces the spacer wafer SW. An optics wafer(“combined optics wafer”) can be provided which incorporates thefeatures and functionalities of said spacer wafer SW. Producing such a“combined optics wafer” may be accomplished using a particular precursorwafer and, manufactured based thereon, a particular semi-finished part.Such a precursor wafer and semi-finished part, respectively, has atleast one structured surface, usually having protrusions extendingvertically beyond at least one of the two surfaces of transparentelements 6 to be provided in the precursor wafer and present in thesemi-finished part, respectively.

In FIG. 10, an example of a such a semi-finished part ow′ (“combinedsemi-finished part”) with one structured surface is schematicallyillustrated. It is readily deduced from FIG. 10, what a semi-finishedpart could look like when it would be used for manufacturing a moduleshown in FIG. 1. Looking upon wafers OW and SW (or wafers OW and BW, orwafers OW and SW and BW) in FIG. 4 as one single part, it can be readilyvisualized what a corresponding optics wafer (“combined optics wafer”)for manufacturing a module according to FIG. 1 and also a correspondingsemi-finished part would look like.

As mentioned before, analogously, a provision of other “combined wafers”is possible, e.g., such that an optics wafer is structured on bothsides, so as to replace baffle wafer BW and spacer wafer SW.

Coming back to FIG. 4: In order to form a wafer stack 2, the wafers arealigned and bonded together, e.g., by gluing, e.g., using a heat-curableepoxy resin. It is usually a critical point to ensure that each activeoptical component (such as the emission members E on the substrate waferPW) is sufficiently accurately arranged with respect to a correspondingpassive optical component (such as lens members L of the optics waferOW).

FIG. 4 shows a cross-sectional view of a so-obtained wafer stack 2 formanufacturing a multitude of modules 1 as shown in FIG. 1. The thindashed rectangles indicate where separation takes place, e.g., by meansof using a dicing saw.

The fact that most alignment steps are carried out on wafer level makesit possible to achieve a good alignment (in particular of members E withrespect to members L) in a rather simple and very fast way. The overallmanufacturing process is very fast and precise. Due to the wafer-scalemanufacturing, only a very small number of production steps is requiredfor manufacturing a multitude of modules 1. High accuracy is readilyachieved, e.g., the wafers to be combined in the wafer stack aremanufactured, the emission members E are mounted using pick-and-place,and then, in one single alignment step, all active (E) and passive (L)optical components are (laterally) aligned with respected to each other,wherein the vertical alignment is taken care of by a spacer wafer SW orby a suitably designed optics wafer OW or substrate wafer PW.

In the embodiments described referring to FIGS. 1 to 10, several aspectsof the invention (cf. section “Background of the Invention”) arerealized. The first aspect of the invention is realized, since alight-emitting module is realized, the second aspect, since the opticswafer OW is partially transparent and partially non-transparent(transparent portions t and blocking portions b), and the fourth aspect,since the substrate wafer is a PCB or PCBA.

FIG. 11 schematically illustrates the manufacture of otheropto-electronic modules 1 and shows a wafer stack 2, the thin dashedrectangles indicating where separation takes place. A transparent opticswafer OW is provided, and the passive optical components L are only veryschematically sketched. E.g., the optical components L could be producedon a glass or transparent polymer plate, e.g., by replication, e.g.,using embossing. Such an optics wafer may be looked upon as atransparent portion with no blocking portion. A non-transparent spacerwafer, e.g., manufactured using replication, e.g., using embossing, anda transparent substrate wafer, e.g., a glass plate or a polymer-basedplate, are provided. Either before wafer stack 2 is formed of wafers OW,SW, PW or after that, active optical components E such as LEDs are(mechanically) attached, usually by bonding, e.g., by gluing. Attachingthe active optical components E is certainly carried out beforeseparating wafer stack 2 into individual opto-electronic modules 1, i.e.is carried out on wafer level, because this way, the handling issimplified, and a high (lateral) alignment precision can be achievedrelatively easily.

Optically active surfaces 14 of the active optical components E facesubstrate wafer PW, and light emitted by them (illustrated by dottedlines) runs through substrate wafer PW. Electrical contacts of theopto-electronic modules 1 are formed by electrical contacts of theactive optical components E. The electrical contacts may be, asillustrated in FIG. 11, solder balls 7, but could also be contact padsor be formed by a lead frame of the active optical components E orprovided differently.

Thus, in the embodiment of FIG. 11, the first and third and fifth andsixth aspects of the invention are combined. It would also be possibleto provide that optics wafer OW is partially non-transparent, e.g., likeshown in FIGS. 3 and 4 (cf. also FIGS. 5 to 9), and thus include alsothe second aspect of the invention.

Using the electrical contacts of the active optical components E ascontacts of the opto-electronic modules 1 will usually not allow toinclude the fourth aspect of the invention in the illustratedembodiment. However, a partially non-transparent substrate wafer PWcould be provided, e.g., based on what has been described above assemi-finished part ow (cf. FIG. 7), manufactured, e.g., like illustratedin FIGS. 5 to 7. Alternatively, a partially non-transparent substratewafer PW could be provided similar to what has been described before asprecursor wafer 8 (cf. FIG. 5).

In particular if at least one of substrate wafer PW and optics wafer OWis partially transparent and partially non-transparent, spacer wafer SWcould be replaced by one of these, by combining the functionalities ofthe respective two wafers (OW and SW, or PW and SW) in one wafer.

When both, substrate wafer PW and optics wafer OW, are partiallytransparent and partially non-transparent, and with spacer wafer SW, ifpresent, non-transparent, opto-electronic modules 1 can be manufacturedfrom which light is emitted only in desired, well-defined ways, moreparticularly only through desired transparent parts such as through thepassive optical components L.

FIGS. 12 to 19 show opto-electronic modules 1 in which the first and thefourth and the sixth aspects of the invention is realized, whereas thethird aspect is not realized therein and usually will not need berealized therein. In these embodiments, PCBs or interposers can be usedas substrate members P, the electrical contacts of the active opticalcomponents E, however realized, being reroutable by the substrate memberP, and the electrical contacts of the opto-electronic modules 1 beingrealized by the substrate members P, realized, e.g., as contact padswithout solder balls or, as shown in the Figures, with solder balls 7.The modules 1 may, as an example, be understood as light-emittingmodules such as flash modules like usable in photographic cameras or insmart phones, the active optical components E thus being light emitterssuch as LEDs. Although the passive optical components L are mostly onlyvery schematically sketched in the Figures and sometimes more explicitlydrawn, they may by any passive optical component or any combination ofany passive optical components. For many typical applications, lenseswill be used, wherein these may be diffractive and/or refractive lenses,and they may be unitary parts or be comprised of two or more parts(e.g., as shown in FIGS. 1, 2 and 4).

From the descriptions of the wafer-level based manufacturing processgiven above, it will be clear, how the embodiments described below canbe manufactured.

FIG. 12 illustrates an opto-electronic module 1 comprising an activeoptical component E which is realized as a lead-frame package (leadframe 15) and mounted on substrate member P. Substrate member P andoptics member O are fixed with respect to each other by spacer member Sadjusting the vertical distance between active optical component E andpassive optical component L. Optics member O can be realized, e.g., asdescribed above in conjunction with FIG. 11. With spacer member S beingnon-transparent, also the fifth aspect of the invention is realized inthis example.

FIG. 13 illustrates a similar opto-electronic module 1 as FIG. 12, buthere, the active optical component E is electrically contacted usingsoldering from the back side, i.e. from that side of the active opticalcomponent E opposite to its optically active surface 14. Active opticalcomponent E can be a packaged component or a bare die. Furthermore, FIG.13 illustrates that passive optical components L may be embodied invarious ways, having any suitable shape for suitably guiding light, inparticular light emitted by active optical component E.

FIG. 14 illustrates a similar opto-electronic module 1 as FIGS. 12 and13, but here, the second aspect of the invention is realized by thepartially non-transparent optics member O having a blocking portion band a transparent portion t, e.g., like shown in FIGS. 1 and 2.Similarly, the second aspect can also be realized in the embodiments ofFIGS. 12 and 13.

Furthermore, in FIG. 14, another way of electrically contacting abare-die active optical component E, namely using wirebonding (wirebond16) and electrically conductive glue 17. One can, e.g., and as shown inFIG. 14, electrically contact the front side of the active opticalcomponent E (from where light is emitted) by means of wire bond 16 whileelectrically contacting the back side by means of conductive glue 17.Both contacts may be directed to contact pads of the PCB or interposerwhich makes up for the substrate member P.

Including an unpacked (bare die) active optical component E in a module1 can allow to realize particularly small modules 1.

FIG. 15 illustrates a similar opto-electronic module 1 as FIGS. 12 to14, but the optics member O also has the functionality of a spacerwafer. This may also be realized in embodiments of FIGS. 12 to 14.Manufacturing steps and alignment steps may be saved this way, andcorresponding modules can be particularly small. Furthermore, it isillustrated in FIG. 15 that an active optical component E (packaged orunpackaged) may be electrically contacted using (solely) conductivesolder 17. Furthermore, the passive optical component L is moreexplicitly drawn as a lens, and in particular as a protruding lens,wherein such kind of passive optical components L may be realized alsoin others of the described embodiments. The second aspect of theinvention is also realized in the embodiment of FIG. 15, since theoptics member O comprises a transparent portion t and a blocking portionb.

FIG. 16 illustrates an opto-electronic module 1 in which a coated spacermember S is comprised. The spacer member S comprises a reflectivecoating 18, e.g., obtained by applying one or more metal layers thereon,e.g., by exposing it to a suitable metal-containing vapor or bysputtering a metal such as aluminium. Alternatively, a dielectricalcoating, in particular a reflective dielectrical coating, could beapplied. As to the way of applying a coating, besides deposition out ofthe vapor phase, e.g., dip coating may be employed. The coating canenhance the optical properties of module 1 and/or be applied forachieving a particular effect for a person looking at the module(through optics member O). In particular, those surfaces of the spacermember S are partially or fully coated which face the inside of module1. Furthermore, these surfaces may be, as shown in FIG. 16, inclinedwith respect to the vertical direction and more particularly describe acone.

Spacer member S can be made substantially of a non-transparent material,e.g., manufactured by means of replication and subsequent coating, butit could also be made substantially of a transparent material, becausethe coating, if fully applied, may inhibit an emission of light throughthe spacer member S.

Because of the provision of transparent portion t and blocking portionb, module 1 embodies the second aspect of the invention. Ways ofrealizing this have been described herein before. But a fullytransparent optics member O could also be provided. A bare-die activeoptical component E is in electrical contact with a PCB substrate memberP by means of solder. Alternatively, one of the other ways of attachingand electrically contacting the active optical component E (packaged orunpackaged) described herein may be used. For strengthening themechanical contact between active optical component E and substratemember P, an underfiller such as a suitable epoxy may be applied betweenthe two (not shown).

FIGS. 17 to 19 schematically illustrate further embodiments ofopto-electronic modules. In the embodiments of FIGS. 17 to 19, themodules 1 comprise two substrate members P, P′. Active optical componentE is (mechanically) fixed to substrate member P which is at leastpartially transparent, e.g., a glass or a polymer plate, andelectrically connected to substrate member P′, e.g., a PCB. Usually, theactive optical component will be electrically contacted after havingbeen mechanically fixed to substrate member P, or this electricallycontacting is accomplished in one process with the mechanical fixing,e.g., in a reflow process. But it is also possible to firstly establishthe electrical connection to substrate member P′ and subsequentlyaccomplish the mechanical fixture to substrate member P. Either way,usually, the active optical components will be placed on the one or theother wafer (P or P′) by pick-and-place onto the respective wafer beforethe wafer stack 2 is formed.

When considering substrate wafer S′, the fourth aspect of the inventionis embodied in FIGS. 17 to 19, wherein substrate wafer S′ usually willnot embody the third aspect of the invention. On the other hand, whenconsidering substrate wafer S, the third aspect of the invention isembodied in FIGS. 17 to 19, wherein substrate wafer S usually will notembody the fourth aspect of the invention.

The active optical components may be packaged or unpackaged. They may beelectrically contacted in any of the described ways, wherein wirebondingto the top surface (facing substrate member P) is expected to render therealization of a well-defined and reproducible distance of the activeoptical component E to the optics member O difficult.

In FIG. 17, it is illustrated that two spacer members S, S′ can beprovided, spacer member S ensuring a desired vertical distance betweensubstrate member P (and thus active optical component E) and opticsmember O. Spacer member S may be coated like discussed in conjunctionwith FIG. 16 and/or may be shaped as discussed in conjunction with FIG.16. The other spacer member S′ is arranged between the two substratewafers P, P′. It increases a mechanical stability of module 1 and can inparticular lead to an increased lifetime of the module by absorbingmechanical (including thermo-mechanical) stress to which the electricalconnection between active optical component E and substrate member E isexposed. In embodiment with (at least) two substrates (P, P′), it canlead to an increased (lateral) alignment accuracy if the electricalconnection of the active optical components E to the one substrate wafer(P′ in FIG. 17) is created after the active optical components E havebeen (placed on and) fixed to the other substrate wafer (P in FIG. 17).

In a module 1 with two substrate members P, P′, at least one spacermember may be replaced by a correspondingly designed other member,namely a substrate member P or P′ or, as illustrated in FIG. 18, by acorrespondingly designed optics member O. And/or one spacer member (S′)can be dispensed with out a replacement, as illustrated in FIG. 19,wherein in the embodiment of FIG. 19, a tube-shaped sleeve or outerjacket 19 is applied individually to each module after separation. Asimilar circumferential outer cover may also be applied to any of theother described embodiments. Such a cover can be made of anon-transparent material, and in that case, efforts to createnon-transparent portions in members which have to be at least partiallytransparent (such as P and O) can be dispensed with, see, e.g.,substrate member P and optics member O in FIG. 19.

A module 1 as illustrated in FIG. 19 can be obtained like a module 1illustrated in FIG. 11, wherein (usually before separating) a (second)substrate wafer such as a PCB is included in the wafer stack 2. Andafter separation, to each module I, a sleeve 19 is attached, e.g., bysliding or shifting in a vertical direction.

In FIG. 19, another exemplary embodiment of a passive optical componentL is illustrated, namely a concave lens, which may be used in otherembodiments described herein, and, vice versa, in a module according toFIG. 19, also other passive optical components may find application,e.g., one of those discussed above.

In FIG. 18, it is illustrated that all members of a module 1 may bedesigned in such a way that all side walls of the module are made ofnon-transparent material. This helps to restrict the places where lightmay leave the module 1, and a particular (usually dark) outer appearanceof the module can be achieved.

Furthermore, FIG. 18 illustrates an opto-electronic module 1 comprisinga prism 20. Such prisms 20 and also differently-shaped fully transparentor in-part-transparent parts or elements forming a top of anopto-electronic module may be manufactured on wafer-level. E.g., moldingmay be used for manufacturing a corresponding wafer, wherein atransparent polymer or a glass may be used (for the polymers inparticular injection molding), but such a wafer could also bemanufactured using replication. It is also possible, in particular incase of glass, to manufacture a corresponding wafer using one or morepolishing processes.

It is to be noted that for wafers (and corresponding members) which havebeen described above and which are non-transparent or comprise at leastone non-transparent portion, not only polymer materials may findapplication, but it would be possible to manufacture the non-transparentparts of a metal material, e.g., of a molded metal, possibly of apolished metal. A metal may provide a particularly good dimensionalstability and mechanical stability. E.g., a precursor wafer such asprecursor wafer 8 shown in FIG. 5 might be embodied as a metal wafer.But polymer wafers will in many cases be lighter and cheaper.

Opto-electronic modules 1 described in the present patent applicationcan have an excellent manufacturability while being very small indimension and having a high alignment accuracy and thus a high quality.

LIST OF REFERENCE SYMBOLS

-   1 device, opto-electronic module, light-emitting module, LED module,    flash light module-   2 device, appliance, wafer stack-   3 transparent region-   4 opening-   5 optical structure, lens element-   6 transparent element-   7 solder ball-   8 precursor wafer-   9 printed circuit board-   10 device, electronic device, smart phone-   11 hole, opening-   12 support layer-   13 support substrate-   14 optically active surface-   15 lead frame-   16 wire bond, wire-bonding wire-   17 electrically conductive glue-   18 coating, reflective coating-   19 sleeve, tube, jacket, cover-   20 passive optical component, prism-   b blocking portion, non-transparent portion-   B baffle member-   BW baffle wafer-   D detecting member, detector, photo diode-   E active optical component, emission member, light emitter,    light-emitting diode-   L passive optical component, lens member-   O optics member-   ow semi-finished part-   ow′ semi-finished part, “combined semi-finished part”-   OW optics wafer-   P substrate-   P′ substrate-   PW substrate wafer-   s1, s2, . . . refers to a sectional view-   S spacer member-   S′ spacer member-   SW spacer wafer-   t transparent portion-   T transparent material

1. A method for manufacturing a device, the device comprising at leastone opto-electronic module, said method comprising the step of c)creating a wafer stack comprising a first wafer, referred to assubstrate wafer, and a second wafer, referred to as optics wafer;wherein a multitude of active optical components is mounted on saidsubstrate wafer, and said optics wafer comprises a multitude of passiveoptical components, and wherein each of said opto-electronic modulescomprises at least one of said active optical components and at leastone of said passive optical components.
 2. The method according to claim1, comprising the step of e) placing said active optical components onsaid substrate wafer by means of pick-and-place.
 3. The method accordingto claim 1, wherein the wafer stack comprises means for ensuring awell-defined distance between said active optical components and saidpassive optical components, the method comprising, in case said meansare comprised in said optics wafer: the steps of f) providing saidoptics wafer, said optics wafer comprising, as said means, verticalprotrusions for ensuring said well-defined distance between said activeoptical components and said passive optical components; and h) attachingsaid active optical components to said wafer stack; wherein step h) isnot carried out before step f) is carried out; and in case said meansare not comprised in said optics wafer: the steps of g1) providing saidoptics wafer; and g2) providing, as said means, at least one spacerwafer for ensuring a well-defined distance between said active opticalcomponents and said passive optical components; h′) attaching saidactive optical components to said wafer stack; wherein step h) is notcarried out before steps g1) and g2) are carried out.
 4. The methodaccording to claim 1, wherein said active optical components are lightemitting components, and wherein each of said opto-electronic modulescomprises exactly one of said light emitting components.
 5. The methodaccording to claim 1, wherein said optics wafer comprises at least oneportion, referred to as blocking portion, which is at leastsubstantially non-transparent for at least a specific wavelength range,and at least one other portion, referred to as transparent portion,which is at least substantially non-transparent for at least saidspecific wavelength range.
 6. The method according to claim 1, whereinsaid substrate wafer substantially in full is transparent for at least aspecific wavelength range or comprises one or more portions in which itis transparent for at least a specific wavelength range.
 7. The methodaccording to claim 1, comprising the step of j) establishing anelectrical connection between each of said active optical components andsaid substrate wafer.
 8. The method according to claim 1, wherein saidsubstrate wafer is a printed circuit board or a printed circuit boardassembly.
 9. The method according to claim 1, wherein the wafer stackcomprises means for ensuring a well-defined distance between said activeoptical components and said passive optical components, wherein saidmeans are comprised in said optics wafer or comprised in said substratewafer or are distinct from these, wherein said means are, at least inpart, made substantially of a material which is at least substantiallynon-transparent for at least a specific wavelength range.
 10. The methodaccording to claim 1, wherein said active optical components areprovided as bare dies.
 11. The method according to claim 1, comprisingthe step of d) separating said wafer stack into a multitude of saidopto-electronic modules, each comprising at least one of said passiveoptical components and, vertically and optically aligned thereto, atleast one of said active optical components.
 12. The method according toclaim 1, comprising the step of k) manufacturing at least a portion ofsaid optics wafer using of replication.
 13. The method according toclaim 1, comprising the step of l) manufacturing said passive opticalcomponents using of replication.
 14. The method according to claim 1,wherein each of said passive optical components is associated with atleast one of said active optical components.
 15. An opto-electronicmodule, comprising a substrate member; an optics member; at least oneactive optical component mounted on said substrate member; at least onepassive optical component comprised in said optics member; wherein theoptics member is directly or indirectly fixed to said substrate member.16. The module according to claim 15, wherein outer bounds of a verticalsilhouette of the opto-electronic module and outer bounds of a verticalsilhouette of said optics member and of said substrate member eachdescribe a substantially rectangular shape.
 17. The module according toclaim 15, wherein said at least one active optical component is exactlyone light-emitting component.
 18. The module according to claim 15,wherein said optics member comprises at least one portion, referred toas blocking portion, which is at least substantially non-transparent forat least a specific wavelength range, and at least one other portion,referred to as transparent portion, which is at least substantiallynon-transparent for at least said specific wavelength range.
 19. Themodule according to claim 15, wherein said substrate membersubstantially in full is transparent for at least a specific wavelengthrange or comprises one or more portions in which it is transparent forat least a specific wavelength range.
 20. The module according to claim15, comprising at least one electrical connection between said at leastone active optical component and said substrate member.
 21. The moduleaccording to claim 15, wherein said substrate member is a printedcircuit board or a printed circuit board assembly.
 22. The moduleaccording to claim 15, comprising means for ensuring a well-defineddistance between said at least one active optical component and said atleast one passive optical component, wherein said means are comprised insaid optics member or comprised in said substrate member or are distinctfrom these, wherein said means are, at least in part, made substantiallyof a material which is at least substantially non-transparent for atleast a specific wavelength range.
 23. The module according to claim 15,wherein said at least one active optical component is at least one baredie.
 24. The module according to claim 15, wherein said substrate memberprovides at least one electrical connection from said active opticalcomponent across said substrate member.
 25. The module according toclaim 15, wherein lateral dimensions of said substrate member and ofsaid optics member are substantially identical.
 26. The module accordingto claim 15, wherein said optics member is aligned generally parallel tosaid substrate member.
 27. The module according to claim 15, whereinsaid substrate member and said optics member are of generally block- orplate-like shape, possibly comprising at least one hole.
 28. Anappliance comprising a multitude of opto-electronic modules according toclaim 15, wherein the appliance comprises a first wafer referred to assubstrate wafer and a second wafer referred to as optics wafer, whereinthe multitude of substrate members is comprised in said substrate wafer,and the multitude of optics members is comprised in said optics wafer.29. An electronic device comprising a printed circuit board and anopto-electronic module according to claim 15 mounted on said printedcircuit board.
 30. The electronic device according to claim 29, whereinthe electronic device is a hand-held communication device or aphotographic device.